i386/ucla/src/lab5/user/cat.c

   1 #include <inc/lib.h>
   2
   3 char buf[8192];
   4
   5 void
   6 cat(int f, const char *s)
   7 {
   8         long n;
   9         int r;
  10
  11         while ((n = read(f, buf, (long)sizeof(buf))) > 0)
  12                 if ((r = write(1, buf, n)) != n)
  13                         panic("write error copying %s: %e", s, r);
  14         if (n < 0)
  15                 panic("error reading %s: %e", s, n);
  16 }
  17
  18 asmlinkage void
  19 umain(int argc, char **argv)
  20 {
  21         int f, i;
  22
  23         argv0 = "cat";
  24         if (argc == 1)
  25                 cat(0, "<stdin>");
  26         else
  27                 for (i = 1; i < argc; i++) {
  28                         f = open(argv[i], O_RDONLY);
  29                         if (f < 0)
  30                                 panic("can't open %s: %e", argv[i], f);
  31                         else {
  32                                 cat(f, argv[i]);
  33                                 close(f);
  34                         }
  35                 }
  36 }